Method for cleaning the oral cavity

ABSTRACT

A method of cleaning an oral cavity, the method including positioning a device suitable for detecting and removing plaque from a surface of the oral cavity within the oral cavity, cleaning and irradiating the surface of a tooth in the oral cavity, the tooth having applied thereto a fluorescent agent, with incident radiation of a wavelength effective to provide a fluorescent emission when contacted with the fluorescent agent on the tooth, collecting at least a portion of the fluorescent emission over a first time period, determining a first average fluorescent emission value (APV 1 ), collecting at least a portion of the fluorescent emission over a second time period, determining a second average plaque value (APV 2 ); and comparing the APV 1  to the APV 2.

FIELD OF THE INVENTION

This invention relates to methods for cleaning surfaces of an oralcavity including, e.g. teeth and gums.

BACKGROUND OF THE INVENTION

Biological deposits generally refer to deposits of material ofbiological origin, such as plaque, bacteria, tartar, and calculus thatare generally regarded as undesirable for dental hygiene. Dental plaqueis a complex organic deposit generated in part by the activity ofbacteria upon surfaces of the oral cavity, such as on the teeth, or uponcontamination from, for example, food deposits on the teeth, gums,tongue, or cheek. Plaque is an undesirable precursor to tooth decay andthe development of dental caries.

It is desirable to detect plaque deposits in the oral cavity to directaction for removal, for example by using toothbrushes (manual or power),tooth floss, tooth picks, or oral irrigators, as detection indicates theareas at which dental cleaning effort should be focused. Such depositscan be difficult to detect in situ/in vivo on the teeth, gums, tongue,or cheek. It is especially important to detect dental plaque. Fordetection of plaque it is known to use fluorescence measurement, inwhich incident radiation is directed at the surfaces of the oral cavity,and fluorescence radiation having characteristics associated with thepresence of biological deposits is emitted from the surfaces and isdetected.

In the state of the art there are two general methods for detectingdental plaque. One method uses primary fluorescence, where thefluorescence of dental plaque or other dental material itself ismonitored. The other method uses secondary fluorescence, where surfacesin the oral cavity suspected of bearing plaque are treated with afluorescent label material which preferentially binds to dental plaque,and the fluorescence emission of the label material on the oral cavitysurfaces to which it has bound is detected to indicate the presence ofdental plaque. Also known are toothbrush heads having a bundle ofoptical fibers extending through it to direct incident radiation at atest tooth surface, and to collect emitted radiation from the test toothsurface.

A requirement of such methods is that incident radiation is directed atthe surfaces of the oral cavity under examination and that consequentfluorescence emission radiation from those surfaces is collected. Theamplitude of that radiation is a function of the amount of biologicaldeposit located on the surface, as well as the distance the light sourceand detectors are from the surface. Consequently, the actual plaquevalue detected will fluctuate depending upon such factors, therebyresulting in a plaque value which may not truly depict the condition ofplaque on the surface of the oral cavity. Known devices are not known tocompensate for distances between the source of radiation and/or sensorsand the surface of the oral cavity when determining the amount ofbiological deposit on the oral cavity surfaces.

Devices and methods for detecting and removing plaque in the oral cavityaccording to the invention described and claimed herein provide improvedmethods of cleaning teeth, particularly where plaque is detected andremoved.

SUMMARY OF THE INVENTION

The invention is a method of cleaning an oral cavity, the methodincluding positioning within the oral cavity a device suitable fordetecting and removing plaque from a surface of the oral cavity,substantially simultaneously cleaning and irradiating the surface of atleast one tooth in the oral cavity, the at least one tooth havingapplied thereto a fluorescent agent capable of binding to plaque on thesurface of the at least one tooth, with incident radiation of awavelength effective to provide a fluorescent emission when contactedwith the fluorescent agent on the surface of the at least one tooth,collecting at least a portion of the fluorescent emission over a firsttime period, determining a first average fluorescent emission value(APV1) based on the fluorescent emission collected over the first timeperiod, collecting at least a portion of the fluorescent emission over asecond time period, determining a second average plaque value (APV2)based on the fluorescent emission collected over the second time period;and comparing the APV1 to the APV2.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the operating principle of devices andmethods of the present invention.

FIG. 2 shows a top plan view of an embodiment of the bristle face of atoothbrush head embodiment of the present invention.

FIG. 3 illustrates an embodiment of a method of the present invention.

FIG. 4 is a sample plot of data produced from an oral cleaning device ofthe present invention.

FIG. 5 is a cross-sectional view of an embodiment of a device for use incleaning surfaces of the oral cavity according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following terms are used interchangeably both in the specificationand the claims. APV is used interchangeably with “average plaque value”.ACPV is used interchangeably with “average compensated plaque value”.PMTP is used interchangeably with “predetermined maximum time period”.

Methods for cleaning a surface of the oral cavity are provided, whichmay include detecting and removing plaque on the surface of the oralcavity, e.g. teeth and gums. The device comprises a radiation source fordirecting incident radiation onto a surface within the oral cavity towhich a fluorescent agent has been bound. “Fluorescent agent”, as usedherein, means a composition or compound applied to the surface of theoral cavity, e.g. teeth or gums, which is capable of binding to plaquepresent on the surface in the oral cavity and is capable of providing afluorescent emission when irradiated with incident radiation of aparticular wavelength. By “binding” or “bound” to plaque, it is meantthat the fluorescent agent is attached to plaque deposits on the surfaceof the oral cavity such that it will not be separated from the plaquedeposit under conditions of cleaning as described herein. For example,brushing of the treated surface with a toothbrush, either manual orpower, will not result in the fluorescent agent being removed from thesurface unless the plaque to which it is attached is removed from thesurface.

The radiation source typically may provide light having a peakwavelength of from about 450 to about 500 nanometers, although the rangemay vary depending upon the particular fluorescent agent applied to thesurface of the oral cavity to be cleaned. The device may optionallyinclude a filter for filtering incident radiation prior to contact withthe surface of the oral cavity to be examined. The device also includesoptical collectors for collecting fluorescent emission, and optionallyreflected light, resulting from contact of the incident radiation withthe treated surface. In certain embodiments, the optical collectors maycomprise optical fibers or filaments. The device also includes anoptical pathway for conveying the collected fluorescent emission andreflected light in the device. In certain embodiments, the opticalpathway may comprise optical fibers. As such, optical fibers may serveboth to collect and convey the reflected light and fluorescent emission.

The device further includes electrical components for sensing, ordetecting, the optical light of the fluorescent emission, means forconverting the optical light signal to an electrical signal and a dataprocessor for manipulating the electrical signal correlating to thecollected fluorescent emission taken over iterative intervals so as todetermine an average plaque value. As such, plaque value, or averageplaque value, as discussed and determined herein, is based upon andcorrelates to the fluorescent emission generated by contact of theincident radiation with the fluorescent agent and collected by thedevice over a particular time period.

In embodiments where both reflected light and fluorescent emission arecollected, the device further includes electrical components for sensingthe optical light signal of the reflective light and the fluorescentemission. In one embodiment, the optical light signals of the reflectivelight and the fluorescent emission are sensed, or detected,sequentially, but essentially simultaneously. By essentiallysimultaneously, it is meant that, while measurements are not takenexactly at the same time, the difference in time between detecting thereflective light and fluorescent light, respectively, is so small thatthe detection of each approximates the simultaneous reading. The devicefurther comprises means for converting an optical light signal to anelectrical signal, for example, a transducer. The devices may includemeans for amplifying or conditioning the electrical signal, thusproviding a smoother or averaged signal, or a signal with reduced noise.The device also includes a data processor which may contain ananalogue-to-digital converter for converting the electrical signal froman analogue format to a digital format. The processor thenmathematically manipulates the electrical signal of the collectedreflected light and fluorescent emission taken over iterative intervalsso as to determine an average compensated plaque value (ACPV) over aparticular time period. By “compensated plaque value”, it is meant thatthe plaque value is determined taking into account the distance betweenthe optical collector and the surface of the oral cavity being examined.As such, the compensated plaque value is determined as a function of thedistance between the optical collector and the surface of the oralcavity at any given moment/reading. As a result of determining plaquevalue as a function of distance, the compensated plaque value sodetermined will be substantially the same for a particular surface atany particular moment/reading, irregardless of the actual distancebetween the radiation source and the surface of the oral cavity beingcleaned. By substantially the same, it is meant that the determinedcompensated plaque value at any given distance will be statistically thesame. The device may be used as a component of, or in combination with,oral cleaning devices such as toothbrushes, whether manual or power.

Methods of the present invention for cleaning surfaces in the oralcavity, e.g. teeth and gums, involve the use of a fluorescent agentapplied to the surface in the oral cavity prior to cleaning. Forexample, fluorescein or salts thereof, e.g. sodium fluorescein, areknown fluorescent agents and may be dispersed in a suitable medium, suchas toothpaste, a dental gel, or a rinse containing the fluorescentagent. The fluorescent agent can be applied either by first rinsing theoral cavity with the fluorescent agent or by applying the toothpaste ordental gel containing the fluorescent agent. The plaque on the surfacesof the oral cavity retains an amount of fluorescent agent bound theretothat is proportionate to the amount of plaque on the surface. Whilefluorescein is one example of a fluorescent agent, other agents areknown that will bind to plaque similar to fluorescein. The particularwavelength of the incident radiation used in methods and devices of thepresent invention will vary, depending on the particular fluorescentagent chosen.

After application of the fluorescent agent to the surface in the oralcavity to be cleaned, the user positions the device that is suitable fordetecting and removing plaque from the surface of the oral cavity withinthe oral cavity and proceeds to clean the surface. The oral cavity maybe partitioned into a plurality of sections, for example, from 4 to 12sections, so that cleaning of the oral cavity can take place in stages,proceeding from one section to another until the entire surface in theoral cavity, e.g. teeth and/or gums, is cleaned. The number of sectionsinto which the oral cavity is partitioned may be pre-selected andprogrammed into the device, as described herein below. Alternately, thenumber of sections may be determined on a continuous basis duringcleaning, based on readings of average fluorescent emission being takencontinuously throughout the cleaning process. In either case, the deviceitself provides a prompt to the user, for example, without limitation,auditory, visual, or vibratory, indicating that the user should move thedevice to another of the plurality of sections in the oral cavity.

In practice, the device is positioned within one of the plurality ofsections of the oral cavity to be cleaned. The device substantiallysimultaneously cleans and irradiates a surface of at least one tooth inthe section of the oral cavity being cleaned with incident radiation.The surface of the tooth in the section being cleaned and irradiated hasapplied thereto a fluorescent agent capable of binding to plaque on thesurface of the at least one tooth. The surface is irradiated withincident radiation of a wavelength effective to provide a fluorescentemission when contacted with the fluorescent agent bound to the plaqueon the surface of at least one tooth.

The method of the invention includes collecting at least a portion ofthe fluorescent emission from the surface being cleaned over a firsttime period and then determining a first average plaque value (APV1).The APV1 is the average plaque value based on multiple fluorescentemission readings collected over the first time period. At least aportion of the fluorescent emission is then collected over a second timeperiod and is a second average plaque value (APV2) is determined basedon multiple fluorescent emission readings collected over the second timeperiod. The APV1 is then compared to the APV2. If the APV1 is greaterthan or equal to the APV2, the surface being cleaned in the section ofthe oral cavity is continuously, substantially simultaneously cleanedand irradiated for a predetermined maximum time period. As such time asthe predetermined maximum time period has expired, the device is movedto another section within the oral cavity for cleaning. If the APV2 isless than the APV1, the device is moved and positioned within another ofthe plurality of sections and the steps of cleaning, irradiating,collecting the fluorescent emission, determining APV1 and APV2 andcomparing the APV1 to the APV2 are repeated in the next section.

In certain embodiments, reflected light resulting from contact of theincident radiation with the treated surface is collected essentiallysimultaneously with the fluorescent emission. In these embodiments, thefluorescent emission values are compensated fluorescent emission values,as defined herein above.

FIG. 1 is a schematic diagram of the operating principle of methods anddevices for cleaning surfaces of the oral cavity according to thepresent invention. The particular embodiment represented is atoothbrush, although other devices for use within the oral cavity alsoare contemplated by the invention. FIG. 2 is a plan view of a toothbrushhead according to the invention, taken from the bristle side of thebrush head. In the embodiment shown, toothbrush head portion 14,represented as a first dashed box on FIG. 1, includes, in addition toconventional bristle tufts 26 for cleaning teeth, radiation source 22and optical fibers 24 a and 24 b for conveying reflected light 33 andfluorescent emission 34 resulting from contact of the surface of theoral cavity with the incident radiation. Head 14 also may include firstoptical filter 42, depending on the radiation source. Althoughstationary bristle tufts 26 for cleaning teeth are shown in FIG. 1, itis to be understood that the device for cleaning an oral cavitydiscussed herein could be a power toothbrush which could use methods ofcleaning teeth and gums such as moving bristle tufts, ultrasonics, orradiation.

Electrical housing 18, represented as a second dashed box in FIG. 1,will contain other electrical components of a plaque detecting devicelocated therein, as described herein above. In some embodiments,electrical housing 18 may reside in a handle portion of the cleaningdevice, for example a toothbrush handle. In the embodiment shown,optical fibers 24 a and 24 b extend from head 14 into electrical housing18. Housing 18 also includes contained therein, second optical filter44, first optical transducer 46, second optical transducer 48, firstamplifier 52, second amplifier 54, data processor 56 and power source 50for operating the electrical components.

FIG. 1 also shows a representative surface of the oral cavity, e.g.tooth 60, with top surface 62 and side surface 64. Though FIG. 1 showsdevice 10 directed at top surface 62 of tooth 60, it is to be understoodthat both top surface 62 and side surface 64 of tooth 60, may becontacted with incident radiation. In addition, such contact may besimultaneously at top surface 62 and side surface 64 of multiple teeth60, depending on the brushing technique of the user. The cleaning devicemay also be directed at other surfaces in the oral cavity, such as thoseof the gums, tongue, or cheek.

In operation, prior to use of the cleaning device, the oral cavity istreated with a fluorescent label material, i.e. a fluorescent agent,which preferentially binds to dental plaque and which produces afluorescent emission when exposed to incident radiation. Depending onthe particular fluorescent agent chosen, the peak wavelength of theincident radiation may vary. In embodiments utilizing fluorescein orsalts thereof, e.g. sodium fluorescein, the incident radiation may havea peak wavelength ranging from about 450 to about 500 nanometers. Onceplaced within the oral cavity, radiation source 22 emits light at a peakwavelength of from about 450 to about 500 nanometers (nm), or about 470nanometers. The light may be passed through first optical filter 42,which removes substantially all light having wavelength above about 510nm. As shown, incident radiation 32 from radiation source 22 is directedat top surface 62 of tooth 60, although as discussed above, the incidentradiation may contact multiple surfaces of the oral cavity, e.g. theteeth. Upon contact with the surface, incident radiation interacts withthe fluorescent agent that has bonded to plaque located on the surfacesof tooth 60. The fluorescent agent then produces a fluorescent emission34 having a peak wavelength of from about 520 to about 530 nanometers. Afirst portion of fluorescent emission 34 provided by the fluorescentagent is collected by optical fibers 24 a and conveyed in the device byoptical fibers 24 a for further mathematical processing. Incidentally, asecond portion of reflected light 33 is essentially simultaneouslycollected and conveyed with the first portion of fluorescent emission34. Fluorescent emission 34 is passed through a second optical filter44, which removes substantially all light of wavelengths below about 515nm, ensuring that essentially no reflected light is passed to the dataprocessor 56. The now filtered fluorescent emission 34 passes throughfirst optical transducer 46 in the form of a photodiode, which convertsthe optical light signal into an electrical signal. The electricalsignal is passed through first amplifier 52 to increase the electricalsignal being passed to data processor 56.

A first portion of the reflected light is collected by optical fibers 24b and conveyed in the device by optical fibers 24 b for furthermathematical processing. Incidentally, a second portion of fluorescentemission 34 is collected and conveyed with the first portion ofreflected light. The second portion of fluorescent emission 34 and thefirst portion of the reflected light are conveyed through second opticaltransducer 48, in the form of a photodiode, which converts the opticallight signal into an electrical signal. While it is an option to providean optical filter to remove substantially all of the fluorescentemission prior to passing through second optical transducer 48, in theembodiment shown, neither the second portion of the fluorescentemission, nor the first portion of reflected light is filtered prior totheir passing through second optical transducer 48, as these signals areused to measure the distance from the radiation source 22 to the surfaceof tooth 60. The unfiltered electrical signal is passed through secondamplifier 54 to increase the electrical signal being passed to dataprocessor 56.

Electronic parts that may be used in plaque detecting device 10 mayinclude Taos TSL12S-LF photodiodes, Opamp Analog AD8544ARZ amplifiers,Semrock fluorescence filters (FF01-500-LP, FF01-475/64), and AtmelATMEGA8L-8AU microprocessor.

Data processor 56 performs a mathematical manipulation on the inputsfrom first optical transducer 46 and second optical transducer 48. Inthe mathematical manipulation, the electrical signal resulting fromfiltered fluorescent emission 34 is modified to account for theelectrical signal received from the unfiltered electrical signal thatwas used to determine distance from the tip of optical fiber 24 b, i.e.the optical collector, to the surface of tooth 60. The relationshipbetween the two signals is experimentally determined by measuring theirrespective signal strengths at known distances from the surface ofobjects coated with a fluorescent agent. The result of the mathematicalmanipulation is a corrected electrical signal which results in acompensated plaque value, as that term is described and defined herein.

FIG. 2 shows a plan view of a first embodiment of a device of thepresent invention. As shown, device 10 is in the form of a toothbrushwith a handle portion 12 and a head portion 14. FIG. 2 shows the bristleface 16 of device 10. Bristle face 16 of head portion 14 is shown asgenerally oval in shape, but it is important that bristle face 16 may bein shapes such as triangle, square, rectangle, trapezoid, and otherpolygons, or circle, ellipse, crescent, deltoid, asteroid, or othercurved shapes.

Radiation source 22, optical collectors and conveyors 24 and cleaningtufts 26 are located on bristle face 16. Radiation source 22, preferablyin the form of a light emitter such as a light-emitting diode (LED),directs incident excitation radiation at the surfaces of the teeth to becleaned. Optical collectors and conveyors 24, typically in the form ofoptical fibers, collect the fluorescent radiation emitted from theteeth. The optical fibers may be made of glasses such as silica, but maybe made of other materials, such as fluorozirconate, fluoroaluminate,and chalcogenide glasses, but may also be in the form of plastic opticalfibers (POFs).

Cleaning tufts 26 are made of approximately 20 to 50 individual bristlesarranged on bristle face 16 in a manner to optimize cleaning of thesurfaces of the teeth. FIG. 1 shows one arrangement of tufts 26 onbristle face 16. It is to be understood that the arrangement of tufts 26on bristle face 16 is not limiting in the scope of the presentinvention. Typical tufts are approximately 0.063 inches (1.6 mm) indiameter, with a cross-sectional area of approximately 0.079 inches² (2mm²). The diameters of commonly used bristles are: 0.006 inch (0.15 mm)for soft bristles, 0.008 inch (0.2 mm) for medium bristles, and 0.010inch (0.25 mm) for hard bristles.

A general problem in the recognition of caries, plaque or bacterialinfection on teeth with the above-described method is found in that thedetected fluorescent radiation can be disruptively superimposed withdaylight or the artificial room lighting. This environmental light canlikewise be reflected from the tooth 60 and thus collected by opticalfibers 24 a and 24 b. The spectral region of the environmental lightlying in the detection region in accordance with the invention resultsin a background signal, i.e. noise, which restricts the sensitivity ofplaque detection.

This problem is effectively resolved in accordance with the invention inthat the incident radiation 32 generated by radiation source 22 isperiodically modulated. In this case, because of the short duration ofthe excited state the fluorescent emission 34 follows the intensity ofthe excitation radiation practically instantaneously. In contrast, theenvironmental light is not periodically modulated and is superimposed onthe detected emission 34 solely as a constant component. For evaluationof the emission 34, now only the radiation modulated with thecorresponding frequency is employed as detection signal and evaluated.In this way, the constant component of the environmental light isquasi-filtered out and plaque is detected virtually independently of theenvironmental light. Since the environmental light is, however,modulated slightly with the frequency of the mains voltage, there shouldbe chosen as modulation frequency for the incident radiation 32 at afrequency which differs distinctively from the mains voltage frequencyand preferably lies in the range between 100 Hz and 200 kHz.

The devices and methods for detecting and removing plaque in the oralcavity may also be used as part of, or in combination with, oral caresystems which track the health of the oral cavity. Such systems canrecord plaque levels on teeth, gum, tongue, or cheek surfaces, beforeand after cleaning operations, as well as the track the plaque of levelsover time, reporting the results to the user, or to dental careprofessionals.

FIG. 3 illustrates a first embodiment method of the present invention.In this embodiment, used to clean teeth, the user is instructed todivide the teeth cleaning operation into a number of sections, and tomove from section to section upon receiving an OUTPUT SIGNAL from oralcleaning device 10. For illustrative purposes, and not meant to belimiting in scope, reference is made to FIG. 1 and the embodiment shownin FIG. 3 uses twelve (12) sections of cleaning: three (3) for the frontside of the top teeth, three (3) for the backside of the top teeth,three (3) for the front side of the bottom teeth, and three (3) for thebackside of the bottom teeth. The order in with the sections are cleanedis not critical to the performance of oral cleaning device 10.

In the first step, oral cleaning device 10 is turned on, and an internalCOUNTER, used to track the number of sections cleaned, a GLOBAL TIMER,and a LOCAL TIMER, are set to zero. Progressing to the next step,incident radiation from radiation source 22 is directed at top surface62 or side surface 64 of a tooth 60 (or teeth) in the section beingcleaned. Processor 56 waits until the strength from the unfilteredelectrical signal that was used to determine distance from the radiationsource 22 to the surface of tooth 60 is above a preset DISTANCETHRESHOLD SIGNAL. This is to insure that radiation source 22 ispositioned within close proximity to the top surface 62 or side surface64 of tooth 60. When the strength from the unfiltered electrical signalis above the preset DISTANCE THRESHOLD SIGNAL, the program progresses tothe next steps, and both the GLOBAL TIMER and the LOCAL TIMER arestarted. If, at any point in the cleaning process, DISTANCE THRESHOLDSIGNAL falls below the preset DISTANCE THRESHOLD SIGNAL, both the GLOBALTIMER and the LOCAL TIMER are stopped, and restarted when the strengthfrom the unfiltered electrical signal rises above the preset DISTANCETHRESHOLD SIGNAL. The GLOBAL TIMER is predetermined and set to a maximumglobal cleaning time period (MGCTP) in which the entire oral cavity willbe cleaned.

Progressing to the next step, processor 56 initiates the algorithm onthe inputs from first optical transducer 46 and second opticaltransducer 48, resulting in a corrected electrical signal. An APV iscalculated from time 0 on the LOCAL TIMER to a predetermined first timeperiod and recorded as APV1. The predetermined first time period couldbe 5 seconds (as shown in FIG. 3), or could be other values such as, butnot limited to, 10, 5, 4, 2, 1, 0.5, 0.25, or 0.01 seconds. In someembodiments, the APV may be calculated by taking data at intervals suchas 1, 0.5, 0.25, 0.125, 0.1, 0.05 0.025, 0.0125, 0.01, or 0.005 secondsfrom time 0 to the predetermined first time period, and averaging thecorrected electrical signal values over the number of data pointsmeasured. The time intervals for data recording may be regular, or canbe randomly chosen over the predetermined first time period.

In the next step of the program, the value of COUNTER is increased by 1.Next, a second average plaque value is calculated from the end of thefirst predetermined time period to a predetermined second time period onthe LOCAL TIMER and recorded as APV2. The predetermined second timeperiod could be 5 seconds (as shown in FIG. 3), or could be other valuessuch as, but not limited to, 15, 12, 10, 8, 6, 5, 3, 2, 1, or 0.001seconds. The APV2 may, in some embodiments, be calculated by taking dataat intervals such as 1, 0.5, 0.25, 0.125, 0.1, 0.05 0.025, 0.0125, 0.01,or 0.005 seconds from the end of the predetermined first time to thepredetermined second time period, and averaging the corrected electricalsignal values over the number of data points measured. The timeintervals for data recording may be regular, or can be randomly chosenover the predetermined second time period.

Next, in a first decision block, the APV2 is compared to the APV1. Ifthe APV2 is less than the APV1, the processor moves to a second decisionblock, as described below.

If the APV1 is greater than or equal to the APV2, the program waits fora predetermined third time on the LOCAL TIMER. The third time period isa local maximum time period for cleaning a particular section of theoral cavity. During the predetermined third time period, the usercontinues to clean the teeth in the section being cleaned to insureadequate cleaning time and plaque removal for the section being cleaned.Predetermined third time could be 10, 7.5, 5 (as in FIG. 3), 4, 3, 2, 1,or 0.5 seconds, and may be determined by routine experimentation withthe oral cleaning device. In the embodiment shown in FIG. 3, the insuredadequate brushing time for each section is 5 seconds, and the maximumcleaning time in each section is 15 seconds.

Upon expiration of the predetermined third time period, or if APV2 isless than APV1, the operating program in processor 56 progresses to thesecond decision block. The value of the running time in the GLOBAL TIMERis compared to the MGCTP. If the value of the running time in the GLOBALTIMER is greater than the MGCTP, the operating program in processor 56has an END signal sent to the user to inform the user that the cleaningprocess is complete. It is important to note that the MGCTP must begreater than the product of the number of preset sections and themaximum time in each section. In the case of the embodiment shown inFIG. 3, the number of preset sections is twelve (12), and the maximumtime in each section is fifteen (15) seconds. So, the MGCTP in theembodiment shown in FIG. 3 is 180 seconds (3 minutes).

If the value of the running time in the GLOBAL TIMER is less than theMGCTP, the operating programming processor 56 progresses to the thirddecision block. In this decision block, the value of COUNTER is comparedto the preset number of sections that are being cleaned. If the COUNTERis equal to the preset number of sections, the operating program inprocessor 56 has an END signal sent to the user to inform the user thatthe cleaning process is complete. As mentioned earlier, the embodimentshown in FIG. 3 uses twelve (12) sections of cleaning.

If the COUNTER is less than the preset number of sections, the operatingprogram in processor 56 progresses to the next step. Here, the LOCALTIMER is reset to zero, and the operating program in processor 56 has anOUTPUT SIGNAL sent to the user to inform the user to move the oralcleaning device 10 to the next section for cleaning. As shown is FIG. 3,the operating program in processor 56 progresses to the next step, wherethe LOCAL TIMER is started, and the program begins a second loop.

The process continues until the cleaning operation is completed in allsections. The END signal sent to the user to inform the user that thecleaning process is complete, as well as the OUTPUT SIGNAL sent to theuser to inform the user to move the oral cleaning device 10 to the nextsection for cleaning, may be in a number of forms. These signals may bein forms directed to any of the five senses: sight, sound, touch, smell,or taste. For example, the handle portion 12 of oral cleaning device 10may have a light, or a series of lights, on its surface, or embedded inthe surface. The lights may be off while the user is cleaning eachsection with device 10. The OUTPUT SIGNAL may be used illuminate thelight(s), informing the user it is time to move to the next section. TheEND signal sent to the user to inform the user that the cleaning processis complete, may be used to have the light(s) flash.

In another embodiment, lights of two colors can be used. Here, anilluminated light of a first color informs the user to remain in thesection they are currently cleaning. When it is time to move to a newsection, the OUTPUT SIGNAL may be used to dim the light of a firstcolor, and illuminate a light of a second color. The END signal may beused to illuminate all of the light(s), or have all of the light(s)flash.

Oral cleaning device 10 may use a sound, or a series of sounds, in asimilar manner. Changing volume, pitch, tone, or frequency are allpossible outcomes from OUTPUT SIGNAL and END signal. In otherembodiments, vibratory motions can be used to inform the user to movefrom section to section, or to inform them that cleaning is complete.

FIG. 5 is a cross-sectional view of an embodiment of a device 100 foruse in cleaning surfaces of the oral cavity according to the presentinvention. The particular embodiment represented is a toothbrush,although other devices for use within the oral cavity also arecontemplated by the invention. As shown in FIG. 6, device 100 has ahandle portion 102, a neck portion 104, and a toothbrush head portion114. Toothbrush head portion 114 includes bristle tufts 126 for cleaningteeth and radiation source 122. Handle portion 102 is hollow, andoptical transducers 146 and 148, amplifiers 152 and 154, data processor156 and power source 150 are contained therein.

The present invention may be better understood with reference to thefollowing examples.

EXAMPLES Example 1 Determination of the Compensated Plaque Value

A plaque detecting toothbrush was created by modifying the head of amanual toothbrush by inserting a blue light-emitting diode (LED) facingoutwards from the head, allowing the light from the LED to illuminatethe tooth surface. The LED was surrounded by an array of 12 fiber opticfilaments, also pointed towards the tooth surface in the areailluminated by the blue LED. The fiber optics passed through the neck ofthe toothbrush to a pair of photo sensors (Taos TSL12S-LF) contained inthe handle section of the toothbrush. The fibers were separated into twogroups. One group passed through an optical filter (Semrock FF01-500/LP)that allowed only wavelengths above 515 nm to pass, while the secondgroup allowed all wavelengths to pass, i.e. no optical filter wasutilized. The filtered light represented the plaque value while theunfiltered light was used to interpret the distance between the opticalcollector, i.e. the tips of the optical fibers, and the surface of thetooth. The output of the photo sensors were connected to amplifiers(Analog devices AD8544ARZ) which in turn were connected to an 8 bitmicrocontroller (Atmel ATMEGA8L-8AU). The microcontroller contained two10 bit analog to digital converters that allowed the information to bemanipulated in a digital format within the microcontroller.

Using this apparatus, experiments were performed by using Typodent teethmodels coated with a simulated plaque material containing a fluorescentmaterial. The artificial plaque was painted onto the tooth surfaces in away that approximated the manner in which plaque grows in the humanmouth. The experiments consisted of positioning the optical collectors,e.g. the tips of fiber optic filaments, at varied distances from thetooth surface so as to enable a relationship to be created between thedistance and the plaque value.

The prototype device was operated with the following set of parameters:

-   -   Sampling at 500 Hz (0.002 seconds), sequentially taking 4        measurements in repeating succession.    -   Averaging every 20 data points per output data value.    -   Device powered by 8-bit microcontroller at 7 MHz clock speed.    -   RS232 readout of data to a spreadsheet, and    -   Ambient light compensation.

The device was placed at distances between 0 and 10 mm from the surfaceof the model tooth surface. Readings were taken with Distance LED on,Distance LED off, Plaque LED on, and Plaque LED off. The value of thesignals for Total Plaque and Total Distance were calculated at eachdistance using:Total Plaque=Plaque LED on−Plaque LED off  (I)Total Distance=Distance LED on−Distance LED off  (II)

Table I shows the measured/calculated values for Plaque LED on, PlaqueLED off, Total Plaque, Distance LED on, Distance LED off, TotalDistance.

TABLE I Distance and Plaque readings from prototype oral cleaningdevice. Dis- Plaque Plaque Total Total tance LED LED Plaque DistanceDistance Distance (mm) On Off A LED On LED Off B 0 331.48 125.26 206.22242.74 80.30 162.44 0.5 356.15 129.00 227.15 268.80 83.15 185.65 1.0355.63 129.53 226.10 285.68 81.84 203.84 1.5 345.75 126.58 219.17 291.4280.96 210.46 2.0 337.68 128.27 209.41 295.05 82.95 212.10 2.5 327.62127.24 200.38 295.38 81.05 214.33 3.0 316.36 127.87 188.49 287.32 81.91205.41 3.5 300.70 122.00 178.70 278.04 77.11 200.93 4.0 296.38 127.90168.48 275.14 81.41 193.73 4.5 277.42 120.84 156.58 260.42 76.53 183.895.0 273.38 128.21 145.17 257.83 81.04 176.79 5.5 220.13 83.10 137.03223.33 54.00 169.33 6.0 258.05 128.67 129.38 242.81 82.48 160.33 6.5249.26 127.68 121.58 233.68 81.00 152.68 7.0 241.89 128.50 113.39 225.6182.33 143.28 7.5 236.22 129.06 107.16 219.78 81.61 138.17 8.0 230.22129.44 100.78 212.61 81.56 131.05 8.5 225.94 129.59 96.35 208.47 82.24126.23 9.0 216.50 128.35 88.15 200.35 81.40 118.95 9.5 214.35 129.0085.35 195.95 81.80 114.15 10.0 212.87 131.33 81.54 194.47 82.93 111.53

The value of Column A (Total Plaque) was plotted against Column B (TotalDistance). The resulting line was curve fitted to the follow straightline equation:Total Plaque=1.304(Total Distance)−66.61  (III)

Since the value of Total Plaque at a distance of 1 mm from the surfaceof the model tooth surface was 226, a Compensated Plaque Value (CPV) wasdetermined using:CPV=226+(1.304(Total Distance)−66.61)/Total Plaque  (IV)

TABLE II CPV as a function of distance for oral cleaning device.Distance Total Plaque (mm) A 0 226.70 0.5 226.77 1.0 226.88 1.5 226.952.0 227.00 2.5 227.06 3.0 227.15 3.5 227.09 4.0 227.10 4.5 227.11 5.0227.13 5.5 227.12 6.0 227.10 6.5 227.09 7.0 227.06 7.5 227.06 8.0 227.048.5 227.02 9.0 227.01 9.5 226.97 10.0 226.97 AVERAGE 227.02 Std. Dev.0.12

The table shows the average calculated CPV independent of distance is227.02, with a standard deviation of 0.012 (0.05%). So, the value of theplaque reading has been compensated for, taking into account thedistance from the optical collector to the surface of the model tooth.

Example 2 Use of the Oral Cleaning Device

The device described in Example 1 was used in a study to clean humanteeth. Participants in the study did not perform any oral hygiene for18-24 hours before the study was performed. The study was conductedusing surrogate brushing by a hygienist using the American DentalAssociation-approved Bass Method. The mouth was divided into 12 equalsections so that each section could be analyzed individually. Themaximum total time period for brushing of each section was predeterminedand set to 10 seconds to simulate an entire mouth brushing time of twominutes. During brushing, the data produced with the device was outputvia serial communication to a PC that recorded the data.

FIG. 4 is a sample plot of the data produced from the device during the10 second brushing of a particular section of the mouth. The dataoscillates up and down because the detecting portion of the brush isrepeatedly traveling over areas within the section containing differentlevels of plaque. A linear trend line drawn through the data shows thereduction of plaque during the 10 second time period.

While the foregoing description and drawings represent exemplaryembodiments of the present invention, it will be understood that variousadditions, modifications and substitutions may be made therein withoutdeparting from the spirit and scope of the present invention. Oneskilled in the art will appreciate that the invention may be used withmany modifications of structure, arrangement, proportions, materials,and components and otherwise, used in the practice of the invention,which are particularly adapted to specific environments and operativerequirements without departing from the principles of the presentinvention. For example, elements shown as integrally formed may beconstructed of multiple parts, or elements shown as multiple parts maybe integrally formed, the operation of elements may be reversed orotherwise varied, or the size or dimensions of the elements may bevaried. Therefore, the presently disclosed embodiments are to beconsidered in all respects as illustrative and not restrictive, thescope of the invention being indicated by the appended claims, and notlimited to the foregoing description.

1. A method for cleaning an oral cavity, said method comprising: a.positioning within a section of said oral cavity a device suitable fordetecting and removing plaque from a surface of at least one tooth insaid oral cavity, b. substantially simultaneously cleaning andirradiating said surface of at least one tooth in said oral cavity, saidat least one tooth having applied thereto a fluorescent agent capable ofbinding to plaque on said surface of said at least one tooth, withincident radiation of a wavelength effective to provide a fluorescentemission when contacted with said fluorescent agent on said surface ofsaid at least one tooth, c. collecting at least a portion of saidfluorescent emission over a first time period, d. determining a firstaverage plaque value (APV1) based on said fluorescent emission collectedover said first time period, e. collecting at least a portion of saidfluorescent emission over a second time period, f. determining a secondaverage plaque value (APV2) based on said fluorescent emission collectedover said second time period; and g. comparing said APV1 to said APV2,wherein reflected light resulting from contact of said incidentradiation with said surface is collected essentially simultaneously withsaid fluorescent emission and said APV1 and APV2 to determine averagecompensated plague value (ACPV) for said APV1 and APV2.
 2. The method ofclaim 1 wherein, if said APV2 is less than said APV1, said device ispositioned within another section of said oral cavity.
 3. The method ofclaim 1 wherein, if said APV1 is greater than or equal to said APV2,said surface in said section is continuously substantiallysimultaneously cleaned and irradiated for a predetermined maximum timeperiod.
 4. The method of claim 3 wherein said predetermined maximum timeperiod is from about 0.5 to about 15 seconds.
 5. The method of claim 1wherein said fluorescent agent comprises fluorescein or a salt thereof.6. The method of claim 5 wherein said incident radiation has a peakwavelength of from about 450 to about 500 nanometers.
 7. The method ofclaim 5 wherein said portion of said fluorescent emission has a peakwavelength of from about 520 to about 530 nanometers.
 8. The method ofclaim 1 wherein said first time period is from about 0.01 to about 10seconds.
 9. The method of claim 1 wherein said second time period isfrom about 0.001 to about 15 seconds.
 10. The method of claim 1 whereinsaid reflected light is simultaneously conveyed with said fluorescentemission through an optical filter prior to conversion of an opticalsignal of said fluorescent emission to an electrical signal of saidfluorescent emission, said filter removing light having a wavelength ofabove about 515 nanometers.
 11. The method of claim 1 wherein saidcompensated APV1 and APV2 are determined as a function of the distancebetween the point of collection of said fluorescent emission and saidsurface of said oral cavity.
 12. The method of claim 11 wherein saidcleaning is effected by sonification, pressurized water and brushing.13. The method of claim 12 wherein said brushing is effected by a powertoothbrush or a manual toothbrush.
 14. The method of claim 1 whereinsaid cleaning is effected by sonification, pressurized water andbrushing.
 15. The method of claim 14 wherein said brushing is effectedby a power toothbrush or a manual toothbrush.